Hypertension is a serious condition that can damage vital organs, such as the heart and kidneys, and other parts of the body, such as the central nervous system. Individuals who have hypertension may have, or be at risk of developing, dangerous diseases such as coronary heart disease and kidney failure. Hypertension, which is the leading modifiable risk factor for cardiovascular disease mortality, causes more than 7 million deaths every year worldwide.
Hypertension is the most common chronic medical condition in developed countries as well as the most common indication for physician visits and prescription medication use. Hypertension affects more than 50 million individuals in the United States and over one billion individuals worldwide, and overall prevalence may continue to increase with the advancing age of the population.
Unfortunately, despite the importance of blood pressure control and the availability of multiple classes of antihypertensive agents, the treatment of hypertension remains suboptimal. Data from the most recent National Health and Nutrition Examination Survey demonstrate that only 34% of patients with hypertension have blood pressures at their therapeutic goal. Additionally, it was shown that the majority of patients with hypertension will require two or more antihypertensive agents to achieve their goal blood pressure. Even with optimal compliance with multiple antihypertensive agents of different classes, a significant fraction of patients will not be able to achieve their goal blood pressure. The overall prevalence of resistant hypertension, defined as elevated blood pressure in spite of the use of three or more antihypertensive agents, is unknown, but small studies suggest that it ranges from 5%-16% in primary care settings to greater than 50% in nephrology clinics. Given data suggesting that increasing age and obesity are important risk factors for the development of resistant hypertension, it is expected that the overall prevalence of this condition is likely to increase due to demographic changes in the population.
Systolic blood pressure tends to increase with age and systolic hypertension is an important health issue, prominent in the elderly (Duprez, Am. J. Med. 121:179-184 (2008)). It has been suggested that this occurs as large vessels such as the aorta lose their elasticity with age and is less able to buffer the pulsative nature of cardiac output. There exists a need for a treatment for patients in such clinical setting, for example, patients with systolic hypertension accompanied with low diastolic pressure (Franklin et al. J. Hypertension 29:1101-1108 (2011).
Metabolic syndrome is a cluster of disorders including obesity, hypertension, hypertrigleridemia, hypercholesterolemia and elevated blood sugar. Individuals with this spectrum of disorders are at increased risk of diabetes, heart disease and stroke. Agents capable of treating more than one of these disorders are desirable.
Hypertensive emergencies are defined as severe elevations in blood pressure associated with resultant organ damage (i.e. pulmonary edema, renal impairment, visual impairment, intracranial hemorrhage, or encephalopathy). The treatment of hypertensive emergencies involves aggressive and controlled blood pressure lowering in a highly monitored intensive care setting using intravenous blood pressure lowering agents. Therapeutic agents and method of treatment is needed to gradually lower blood pressure and minimize damage of end organs such as the brain, kidney, heart, and eye.
The frequency of chronic kidney disease also continues to increase worldwide as does the prevalence of end-stage renal disease. Although chronic kidney disease is often caused by hypertension, other factors such as a decrease in renal blood flow and increase in sodium retention or reabsorption can lead to renal diseases. Increased age and diabetes can also contribute to renal disease. Especially the elderly, which are a growing segment of the world population, are at increased risk for renal disease. The presence of chronic kidney disease is also associated with a large increase in cardiovascular morbidity and mortality. Consequently, the identification and reduction of chronic kidney disease has become a vital public health priority.
Thus, there remains a need for new and useful agents that are capable of (i) reducing an individual's blood pressure and/or (ii) promoting renal blood flow and/or (iii) inhibiting or decreasing sodium reabsorption.